## Bug description The hosted GitHub MCP `search_issues` tool silently returns materially incorrect keyword search results while reporting `incomplete_results: false`. This reproduces when calling the hosted endpoint directly, without an MCP aggregator. ## Environment - Endpoint: `https://api.githubcopilot.com/mcp` - Server: `github-mcp-server` - Reported version: `github-mcp-server/remote-34ac9c16f8fd3e2a5af74929de89de3a11e98f9b` - Protocol negotiated: `2025-11-25` - Date verified: 2026-08-31 ## Reproduction Call `search_issues` with ordinary GitHub issue search syntax already scoped to issues. | Query | Hosted MCP `total_count` | GitHub REST `GET /search/issues` | |---|---:|---:| | `repo:modelcontextprotocol/python-sdk transport` | 0 | 410 | | `repo:modelcontextprotocol/python-sdk windows` | 0 | 95 | | `repo:anthropics/claude-code hooks` | 3 | 8016 | | `memory leak` | 40 | 407744 at verification time | The three returned `hooks` results were titled `plugins`, `trap`, and `Hook before Exit`, which also does not match normal GitHub full-text search behavior. Passing `owner` and `repo` separately with a keyword-only `query` produced the same incorrect results, so this is not limited to embedding `repo:` in `query`. Qualifier-only searches such as `repo:modelcontextprotocol/python-sdk label:bug` return plausible counts, which makes the keyword failure easy for an agent to trust silently. ## Expected behavior `search_issues` should preserve GitHub issue search semantics and return counts/results consistent with the GitHub REST Search API for the same effective query, or return an explicit error/unsupported-query signal. ## Actual behavior The tool returns a successful response with `incomplete_results: false`, but keyword matches are missing or unrelated. ## Impact Agents can incorrectly conclude that an issue, bug report, or prior discussion does not exist. This is a correctness failure rather than only a ranking-quality difference.